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  1. K

    The right tool

    Why are people designing electronics at the fringe. They use a 10 amp supply for a 10mA application. If the chip says 0 to 18 volts, they use 2. They use a 10MHz scope to measure 10MHz. They use complicated testing devices, but aren't completely sure of what they are measuring.
  2. K

    Stupid observation

    My wrist strap has a current limiting resistor for my protection. This won't help one iota if a touch high voltage. Is this about freedom from liability?
  3. K

    Why Sink current is higher than Source current?

    I think it's really arbitrary. The goal is to design a circuit that is sufficient for a large signal. It's like cracking open any old circuit and asking, " Why is that current there, higher than that current there?" The large voltage swing lends itself to that.
  4. K

    Project: Voltage tester for BT line

    Maybe this will help. I have a test lab that has a transformer. A ground wire is run from one secondary to another on the same transformer. Although always at the same potential,
  5. K

    Voltage

  6. K

    voltage regulators

    Thanks Audioguru. I really enjoy your articles. In this post, I was taking a positive 5 volt regulator and applying that to a positive 18 volt regulator through a resistor. A simple NPN pass transistor, in this case, can't operate. But if you add the other complimentary transistor, then the...
  7. K

    RLC phase relative to source

    Ever plotted phase shift? I created a peak to peak voltage divider with a series RC. I set the input to be a triangle and the phase shift to be 45 degrees. I happened to notice that all three voltages had to be in phase at peak source voltage. So I am thinking that phase shift occurs on the...
  8. K

    signal waveform generator

    My test lab uses an 8038. The output goes to an opamp followed by an emitter follower pole. That circuit really holds up to abuse! I waste transistors all the time, but that circuit never causes any trouble.
  9. K

    Voltage

    We are accustomed to maintaining differences of potential in electronics. But isn't the voltage level, of let's say a rock of copper, an absolute. I believe that in theory, you could just use one probe to measure voltage. Never seen a voltage meter with one probe, but there could be one, since...
  10. K

    voltage regulators

    I was working with independent power souces when I discovered that the book example of a voltage regulator falls short. It appears that a single pass transistor is not adequate if the regulator is to sink current. You must have a complementary transistor. Can anyone corroborate this?
  11. K

    BENCH POWER SUPPLY

    Something to be aware of is the current capability of some of the more popular regulators. You'll never be able to utilize those high current transistors without either using two in parallel or going with a higher current regulator.
  12. K

    BJT power supply

    The regulator does not have output filtering as switching regulators must have. Is the 555 really prepared to deliver a linear result under a massive voltage swing and load on the 555 that could be anything given the the surrounding circuitry. Don't like switching regulators to begin with and I...
  13. K

    BJT power supply

    Alun, if you have definitely identified a voltage doubler circuit and you know approximately what the voltages are, could you please explain the circuit.
  14. K

    phase shift and feedback

    The way I understand it, phase shift is detrimental to the effects of feedback. We know that the phase shift caused by a transistor of 180 degrees is different from the phase shifts caused by reactive components. In fact, while the transistor phase shift produces an exact replica of the input...
  15. K

    Thermistor with op-amp

    If you ask me, I would say the inputs are biased around 6 or 7 volts and the gain is reduced to some unknown value but not open loop.The gain is still very high so any difference will send the output away from the 6 volt midpoint. The signal is inverted. There is not much positive feedback and...
  16. K

    test equipment bandwidth

    Does anybody know why they can claim good accuracy with equipment at all frequencies extending down to 0 hz. From what I have seen, the more you pay the higher the frequency that can measured. Now, does that mean you are paying for the extra circuits that are put into the equipment so that you...
  17. K

    p type and n type

    I think that sometimes authors are confused about how to explain electrons and holes. I have read that holes don't move, and I have read that holes are pushed into the n type material. I think it is easier to explain from the viewpoint of atomic structure. P type material is made such that there...
  18. K

    Power Amp

    Okay. So why go to the trouble of even biasing the thing. Let's say that we can use virtually any supply voltage, any gain, any load, any input, and at any frequency so long as it's a modern opamp. And we still don't have to worry about the integrity of the signal.
  19. K

    Power Amp

    You can do it that way, but isn't the main reason for the emitter followers the current gain. I know that opamps have emitter followers, but I doubt they were ever intended to deliver signals of large amplitude. This is because of nonlinearity produced by the extreme change in VCE of the...
  20. K

    Impedance matching.

    There is an easy way to remember how to calculate the reflected impedance. I know it's the turns ratio squared times RL but I can never remember if it's the primary over the secondary or the other way around. If you step down the voltage on the load, you decrease the current. Whenever you...
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